A Bimetallic Silver-Neodymium Theranostic Nanoparticle with Multimodal NIR/MRI/CT Imaging and Combined Chemo-photothermal Therapy

An engineered metallic nanostructure is an excellent candidate for "theranosis" of cancer, having intrinsic properties of multimodal imaging and therapy. Toward this target, the development of silver-neodymium bimetallic nanoparticles (Ag-Nd BNPs) via microwave-assisted polyol synthesis is presented. The resultant Ag-Nd BNPs exhibit good monodispersity with average size of 10 nm, fluorescence in the near-infrared (NIR) region, and magnetic properties. The Ag-Nd BNPs also validate MRI, CT, and NIR trimodal imaging ability and enunciate valuable temperature response upon irradiation under a NIR laser. Aided by chitosan functionalization on the surface, the Ag-Nd BNPs deliver good biocompatibility and also promote the loading of paclitaxel, an anticancer drug. Isothermal titration calorimetry affirms the combination of strong binding affinity of drug and high loading efficiency of 7 drug molecules per nanoparticle. Moreover, Ag-Nd BNPs also illustrate a highly efficient photothermal effect in PBS. Therefore, the synergistic effects of paclitaxel and the photothermal effect make BNPs excellent "combined therapeutic agents", and also give them the important ability to destroy cancer cells in vitro at very low dose in comparison to single therapy. Thus, the Ag-Nd BNPs unveil a combination of MRI/CT/NIR imaging and chemo-photothermal therapy that ensures accurate diagnosis at an early stage and comprehensive eradication of tumor cells without affecting healthy cells.

Gadolinium Doping in Zirconia-Toughened Alumina Systems and Their Structural, Mechanical, and Aging Behavior Repercussions

A series of Gd³⁺ dopings in zirconia-toughened alumina (ZTA) systems were undertaken to explore the resultant structural, morphological, hydrothermal aging, and mechanical behavior and imaging contrast abilities. The results from the characterization techniques demonstrate the significance of Gd³⁺ in preserving the structural stability of ZTA systems. ZTA undergoes phase degradation with 10 wt % Gd³⁺ at 1400 °C, while the 100 wt % Gd³⁺ yields GdAlO₃ even at 1200 °C. Gd³⁺ doping at the intermediate level preserves the structural stability of ZTA systems until 1400 °C. Gd³⁺ occupies the ZrO₂ lattice, and its gradual accumulation induces tetragonal ZrO₂ (t-ZrO₂) to cubic ZrO₂ (c-ZrO₂) phase transition. α-Al₂O₃ crystallizes at 1200 °C and remains unperturbed except for its reaction with the free Gd³⁺ ions to yield GdAlO₃. Aging studies and mechanical tests signify the impeccable role of Gd³⁺ in ZTA systems to resist phase degradation. Further, the imaging contrast ability of ZTA systems due to Gd³⁺ doping is verified from the in vitro magnetic resonance imaging (MRI) tests.

A nomogram for predicting the risk of neck node metastasis in pathologically node-negative oral cavity carcinoma

OBJECTIVE

To generate a nomogram for predicting the risk of neck node metastasis in pathologically node-negative patients using a combination of variables comprising of protein expression, ultrastructural alterations and clinicopathological parameters.

MATERIALS AND METHODS

Surgically removed oral tumours (n = 103) were analysed for the expression of desmosomal and hemidesmosomal assembly proteins by immunohistochemistry and ultrastructural alterations by transmission electron microscopy (TEM). Protein expression, ultrastructural alterations and clinicopathological variables were used to construct nomogram from the training set in 75 patients. Clinical utility of the nomogram was validated in a discrete set of 28 patients.

RESULTS

Univariate and multivariate analyses were performed on the training set, and obtained significant variables comprising of integrin β4 expression (p = .027), number of hemidesmosomes (p = .027)/desmosomes (p = .046), tumour differentiation grade (p = .033) and tumour thickness (p = .024) were used for construction of the nomogram. The area under the curve was calculated for both training 0.821 (95% CI 0.725-0.918) and validation sets 0.880 (95% CI 0.743-1.000). The nomogram demonstrated a predictive accuracy of 73.3% and 78.6% with the sensitivity of 81.4% and 83.3% in the training and validation sets, respectively.

CONCLUSIONS

The nomogram constructed on postsurgical tumour samples will be a value addition to histopathology for the detection of neck node metastasis in pathologically node-negative patients.

Iron doped β-Tricalcium phosphate: Synthesis, characterization, hyperthermia effect, biocompatibility and mechanical evaluation

The ability of β-Tricalcium phosphate [β-TCP, β-Ca₃(PO₄)₂] to host iron at its structural lattice and its associated magnetic susceptibility, hyperthermia effect, biocompatibility and mechanical characteristics is investigated. The studies revealed the ability of β-Ca₃(PO₄)₂ to host 5.02mol% of Fe³⁺ at its Ca²⁺(5) site. Excess Fe³⁺ additions led to the formation of trigonal Ca₉Fe(PO₄)₇ and moreover a minor amount of CaFe₃(PO₄)₃O crystallization was also observed. A gradual increment in the iron content at β-Ca₃(PO₄)₂ results in the simultaneous effect of pronounced hyperthermia effect and mechanical stability. However, the presence of CaFe₃(PO₄)₃O contributes for the reduced hyperthermia effect and mechanical stability of iron substituted β-Ca₃(PO₄)₂. Haemolytic tests, cytotoxicity tests and ALP gene expression analysis confirmed the biocompatibility of the investigated systems.

Impact of microRNA dynamics on cancer hallmarks: An oral cancer scenario

MicroRNAs are endogenous small noncoding RNAs that negatively regulate gene expression at posttranscriptional level. The discovery of microRNAs has identified a new layer of gene regulation mechanisms, which play a pivotal role in development as well as in various cellular processes, such as proliferation, differentiation, cell growth, and cell death. Deregulated microRNA expression favors acquisition of cancer hallmark traits as well as transforms the tumor microenvironment, leading to tumor development and progression. Many recent studies have revealed altered expression of microRNAs in oral carcinoma with several microRNAs shown to have key biological role in tumorigenesis functioning either as tumor suppressors or as tumor promoters. MicroRNA expression levels correlate with clinicopathological variables and have a diagnostic and prognostic value in oral carcinoma. For these reasons, microRNA has been a hot topic in oral cancer research for the last few years. In this review, we attempt to summarize the present understanding of microRNA deregulation in oral carcinoma, their role in acquiring cancer hallmarks, and their potential diagnostic and prognostic value for oral cancer management.

Sequential elucidation of the β-Ca3(PO4)2/TiO2 composite development from the solution precursors

The sequential formation of β-Ca₃(PO₄)₂/TiO₂ composites with assorted ratios synthesized from the solution precursors is described. The phase evolution of the synthesized powders to yield a composite during progressive heat treatments is determined through a set of analytical techniques. Investigation reveals the initial crystallization of apatite and anatase TiO₂ (a-TiO₂) mixtures at <800 °C. β-Ca₃(PO₄)₂ crystallizes at ∼800 °C and its subsequent stability is retained until 1300 °C. Besides, a gradual phase transition of a- → rutile TiO₂ (r-TiO₂) transpires in the range of 800-1000 °C before the complete r-TiO₂ transformation accomplishes at 1100 °C. The structural stability of the resultant β-Ca₃(PO₄)₂/r-TiO₂ composites is retained until 1300 °C. The β-Ca₃(PO₄)₂ lattice also hosts a selective amount of Ti⁴⁺ and as a consequence the anticipated β- → α-Ca₃(PO₄)₂ conversion that occurs at 1180 °C is delayed. TiO₂ plays a crucial role in the attainment of dense and pore free microstructures of β-Ca₃(PO₄)₂/r-TiO₂ composites. The mechanical properties determined through nanoindentation revealed an upsurge trend as a function of TiO₂ content in the composites.

Substance abuse amongst the medical graduate students in a developing country

Background & objectives:

Substance abuse is found worldwide including among students. We carried out this study to estimate the prevalence of substance abuse among medical student studying in a medical college in north India.

Methods:

Using a validated questionnaire a cross-sectional survey was conducted among 230 undergraduate and postgraduate medical students in a private medical college.

Results:

The prevalence of substance abuse was 20.43 per cent (47/230) among medical students. An increase in substance abuse was observed in the latter years of medical education. A total of 43 of 47 (91.7%) students using these substances were aware of the ill effects. The most common reasons for substance use were relief from psychological stress (34/47, 72.4%) and occasional celebration (34/47, 72.4%). Of the 47 substance users, 28 (59.6%) made past attempts to quit the substance abuse.

Interpretation & conclusions:

Nearly one-fifth of medical students abuse at least one substance despite knowing the ill effects with the main predisposing factor being the psychological stress.

Stabilization of a t-ZrO2 polymorph in a glassy SiO2 matrix at elevated temperatures accomplished by ceria additions

Cerium additions into the SiO₂–ZrO₂ binary system delay SiO₂ crystallization at elevated temperatures with Ce⁴⁺ occupancy at the t-ZrO₂ lattice for minor additions whereas its excess additions crystallize as discrete CeO₂.

Structural analysis and magnetic induced hyperthermia of Fe3+and Mn2+substituted β-Ca3(PO4)2

Fe³⁺/Mn²⁺co-substitutions in β-Ca₃(PO₄)₂elicit a good hyperthermia effect and biocompatible features.

Microwave Synthesis of Chitosan Capped Silver-Dysprosium Bimetallic Nanoparticles: A Potential Nanotheranosis Device

Accurate imaging of the structural and functional state of biological targets is a critical task. To amend paucities associated with individual imaging, there is high interest to develop a multifunctional theranostic devices for cancer diagnosis and therapy. Herein, chitosan coated silver/dysprosium bimetallic nanoparticles (BNPs) were synthesized through a green chemistry route and characterization results inferred that the BNPs are crystalline, spherical, and of size ∼10 nm. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and X-ray photoelectron spectroscopy (XPS) confirm the reduced metallic states of Ag and Dy in nanoparticles. These BNPs demonstrate high emission in a second near-infrared (NIR-II, 1000-1400 nm) biological window on excitation at 808 nm. Moreover, magnetization and magnetic resonance imaging (MRI) studies perceive the inherent paramagnetic features of Dy component that displays dark T₂ contrast and high relaxivity. Due to high X-ray attenuation effect, BNPs exhibit better Hounsfield unit (HU) value than the reported contrast agents. BNPs unveil good biocompatibility and also express sturdy therapeutic effect in HeLa cells when tethered with doxorubicin.

In Situ Impregnation of Silver Nanoclusters in Microporous Chitosan-PEG Membranes as an Antibacterial and Drug Delivery Percutaneous Device

An in situ synthesis method for preparing silver nanoclusters (AgNCs) embedded in chitosan-polyethylene glycol (CS-PEG) membranes is disclosed. The aim is to develop implantable multifunctional devices for biofilm inhibition and drug release to reduce percutaneous device related complications (PDRCs). A multiple array of characterization techniques confirmed the formation of fluorescent AgNCs with sizes of ∼3 nm uniformly distributed in CS-PEG matrix and their active role in determining the fraction and interconnectivity of the microporous membranes. The presence and increasing contents of AgNCs enhanced the mechanical stability of membranes and decreased their susceptibility to degradation in the presence of lysozyme and H₂O₂. Moreover, the presence and increasing concentrations of AgNCs hindered biofilm formation against Escherichia coli (Gram negative) and Staphylococcus aureus (Gram positive) and enabled a sustainable release of an anti-inflammatory drug naproxen in vitro until 24 h. The overall results gathered and reported in this work make the AgNCs impregnated CS-PEG membranes highly promising multifunctional devices combining efficient antibacterial activity and biocompatibility with active local drug delivery.

Substitutional limit of gadolinium in β-tricalcium phosphate and its magnetic resonance imaging characteristics

To compensate the limitations of bone tissue magnetic resonance imaging (MRI), a series of gadolinium (Gd³⁺ ) substituted β-Tricalcium phosphate [β-TCP, β-Ca₃ (PO₄ )₂ ] were developed. All the powders were characterized using XRD, Raman spectroscopy, Rietveld refinement of the XRD data and the studies confirmed the Gd³⁺ occupancy at Ca²⁺ (1), Ca²⁺ (2) and Ca²⁺ (3) lattice sites of β-Ca₃ (PO₄ )_2. HR-TEM analysis revealed the spherical nature of particles with diameter about 100 nm. The Gd³⁺ doped β-Ca₃ (PO₄ )₂ exhibited non-toxic behaviour to MG-63 cells in vitro and the room temperature magnetic field versus magnetization measurements confirmed its paramagnetic behaviour. MRI analysis revelas that it shorten both T₁ and T₂ proton relaxation times, thus influencing both r₁ and r₂ relaxivity values that reach 61.97 mM^-1 s^-1 and 73.35 mM^-1 s^-1 . © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2545-2552, 2017.

Direct-to-physician and direct-to-consumer advertising: Time to have stringent regulations

BACKGROUND

Direct to physician advertisements and direct to consumer advertisement (DTCA) is a well-known marketing strategy of pharmaceutical companies. Studies from the West and also from the Indian sub-continent revealed several lacunae in such advertisements.

OBJECTIVES

The present study was carried out to understand the international and national scenario regarding the lacunae in drug advertisements and the opinion of both physicians and patients regarding DTCA.

METHODS

The present study was conducted after obtaining approval from the institutional ethics committee. Warning letters (WLs) issued to pharmaceutical companies by United States Food and Drug Administration (USFDA) and Therapeutic Goods Administration (TGA) due to discrepancies in the advertisements were analyzed for reasons that were grouped into one of the following categories: overstatement of efficacy; unapproved indication; lack of adequate directions to use; omission of adverse effects; misleading claims; advertisement made for an unapproved drug (investigational new product). Drug advertisements in Current Index of Medical Specialties (CIMS) April-July 2014 issue was also analyzed for lacunae depending on categories as mentioned above. Physicians and patients in a tertiary care medical college and hospital were administered a validated questionnaire exploring their views about crucial aspects of DTCA. Descriptive statistics was used for each of the categories.

RESULTS

A total of 93 WLs issued by USFDA and 36 by TGA were assessed. Majority of the WLs by USFDA were issued for omission of adverse effects (61/93, 65.6%) followed by misleading claims (54/93, 58.1%). Similarly, WLs by TGA were also mainly issued for the presence of misleading claims (35/36, 97.2%) followed by overstatement of efficacy (26/36, 72.2%) and CIMS evaluation had revealed that 78/92 (84.8%) advertisements omitted adverse effects, 20/92 (21.7%) had misleading claims, 9/92 (9.8%) had unapproved indications and 7/92 (7.6%) overstated the efficacy. With regard to the opinion regarding DTCA, 69.9% physicians had a patient discussing DTCA that was clinically inappropriate. One hundred (64.5%) out of 155 physicians opined that DTCA encourage patients to attend physicians regarding preventive healthcare. On the contrary, 82/155 (52.9%) physicians felt that DTCA would damage the same. Similarly, 69 out of the total 100 patients felt that drug advertisements aid them to have better discussions with their treating physicians. Surprisingly, a large majority (91/100) were of the opinion that only safe drugs are allowed to be advertised.

CONCLUSION

To conclude, from the findings of this study both the physicians and patients should be cautious and not overzealous while dealing with drug advertisements or promotional literature. More stringent scrutiny and issue of WLs or blacklisting of indulging pharmaceutical companies are mandatory by the regulatory agency to contain the same.